It is the first time such a senior figure from the Crown Prosecution Service has travelled to Portugal in connection with Madeleine’s dis­appearance and her presence, along with her deputy, fuelled speculation that a new inquiry is about to be launched.

A fresh probe, probably jointly funded by Britain and Portugal, will look into at least 20 new suspects identified by Scotland Yard’s Operation Grange.

Home Secretary Theresa May is shortly expected to announce a new investigation into Madeleine’s disappearance six years ago at the age of three.

A CPS spokeswoman said: “Prosecutors from CPS London and ­investigators from the Metropolitan Police Service visited their Portuguese counterparts on April 17-18 to discuss possible next steps in ­relation to the disappearance of Madeleine McCann. We continue to work with the police on this case.”

The McCanns’ spokesman Clarence Mitchell said they would not comment publicly while Operation Grange continues.

He said: “They remain grateful, however, to the UK authorities for the work being done to establish what happened to Madeleine and to bring those responsible for her abduction to justice.”

Mrs Saunders, a possible successor to retiring Director of Public Prosecutions Keir Starmer, QC, was joined by her deputy Jenny Hopkins on the trip to Portugal.

It came after the Yard team identified fresh suspects. The Portuguese authorities say they require new information to justify re-opening the inquiry.

Operation Grange, conducted by Scotland Yard’s Homicide and ­Serious Crime Command, was launched in May 2011.

Last month Detective Chief Superintendent Hamish Campbell said the review had identified “both investigative and forensic opportunities” and “more than a handful of people of interest”.

As they marked the sixth anniversary of Madeleine’s disappearance last month, Mr and Mrs McCann said they were encouraged by ­Operation Grange and added that police seemed “more determined than ever”.

The couple’s hopes were further reinforced by the recent ­discovery of three women held ­captive in Ohio since being kidnapped as children. Amanda Berry, Gina DeJesus and Michelle Knight went missing 10 years ago in separate incidents.

Kate and Gerry McCann talk to the media in an apartment in Praia Da Luz, Portugal

They remain grateful, however, to the UK authorities for the work being done to establish what happened to Madeleine and to bring those responsible for her abduction to justice

Clarence Mitchell

When the women were found, the McCanns said the rescue “reaffirmed” their hope of finding their daughter, which has never diminished. It has been reported that Home Secretary Theresa May is set to announce a full-scale Scotland Yard investigation into Madeleine’s disappearance.

A full investigation would allow police to interview suspects in Britain, though they would seek the assistance of the Portuguese to carry out their inquiries there. A Home Office spokesman said: “The Home Office remains committed to supporting the search for Madeleine McCann and we have always said we would provide the Metropolitan Police with the resources they need to investigate her disappearance.”

Madeleine vanished from her ­family’s holiday apartment as her mother Kate, 45, and father Gerry, 44, dined with friends nearby in the Algarve resort of Praia da Luz in May, 2007.

Operation Grange was launched after the couple, both doctors from Rothley, Leicestershire, appealed to David Cameron.

In all, the Grange squad has ­identified around 200 potential leads. Yard officers have travelled to ­Portugal and Spain several times.